Although the following description refers to a tool bag it will be appreciated by the person skilled in the art that the apparatus for detecting the presence of articles in a container can be used in any portable container, for example, tool cabinets, tool cupboards, tool boxes, backpacks, and the like, and it is not limited to tool bags.
The use of tool bags to contain tools and accessories for tools is well known. When a user is performing a job on site tools and other articles are routinely removed from a tool bag to perform the job but they may not be replaced in the tool bag after the job is finished. The tools and other articles may remain at the job site and/or become lost. This is a problem because many tools are expensive to replace. It is also problem in industrial environments where mislaid tools or other articles risk causing damage to machinery. Many industrial environments, for example, aerospace, railway, shipbuilding, nuclear, automobile, or petrochemical sectors, are particularly sensitive to what is referred to as ‘foreign object damage’ (FOD) to their machinery. Naturally, these sectors are particularly interested in foreign object exclusion solutions.
German utility model No. DE 202 07 572 U1 discloses a tool box carried by craftspeople to jobs outside their own workshop. The tools do not have a space permanently allocated to them in the tool box. Instead, the tools lie loosely in disorder in the tool box. Whilst this may be an efficient use of space within the tool box, it is not easy to visually inspect which tools are in the tool box. So, each tool comprises a smart label like that known in the retail industry. The tool box comprises an interrogation device. Upon activation, the interrogation device determines the completeness or incompleteness of the tools in the tool box. The interrogation device may be programmed to determine which tools are missing and indicate them on a display.
A smart label may be a Radio Frequency Identification (RFID) device. An RFID device is any electronic identification device, such as a transponder, that may be attached to an article to identify and track its signature via the medium of a radio-frequency signal. In practice, a RFID device is attached to an article, and a RFID reader like the interrogation device of DE 202 07 572 U1 senses the presence and identifying information associated with the RFID device. The RFID device may be active, semi-active, or passive and may or may not include storage memory. The RFID device contains information like, for example, the type and serial number of the article to which it is attached.
United Kingdom patent publication No. GB 2 451 957 A discloses a tool box equipped with a handle, a detection means, an activation button, an alarm and an LCD display screen. In use, the tool box contains a number of tools each tagged with a respective RFID device which the tool box is intended to transport from site to site. The RFID devices are registered to their corresponding tools on an external computer and the registration data is downloaded to the tool box. The detection means is configured to detect if any tools are missing from the tool box using the registration data. When a user arrives at site, the activation button is pressed, the detection means scans the contents of the tool box and records the RFID-tagged tools into a first inventory stored in a memory of the detection means. Once the job is complete, the user gathers the RFID-tagged tools and replaces them in the tool box. The activation button is pressed again, the detection means scans the contents of the tool box and compiles a second inventory for comparison with the first inventory. If the detection means identifies that any RFID-tagged tools are missing that were present the first time the activation button was pressed, the alarm sounds to alert the user. The identity of the missing tool and its RFID device number are displayed to the user on the LCD screen. GB 2 451 957 A discloses a variant tool box where the detection means continually scans the presence of RFID-tagged tools in the tool box. The variant detection means alerts the user if any RFID-tagged tools are missing when the tool box lid is closed.
The maintenance sector, particularly the aero-engine maintenance sector, is especially sensitive to what it also calls FOD caused by stray tools and other parts contaminating machinery which can lead to machinery damage and ultimately failure. Devices for identification and recovery of RFID-tagged tools and parts contribute to minimizing FOD. The detection means of the tool box of GB 2 451 957 A may potentially detect the RFID-tagged tools when they are close to, but not in, the tool box. This may leads to false detections which make the user think that RFID-tagged tools are in the tool box when in fact they are not. The user may depart from the work site, leave stray RFID-tagged tools behind and not realise that they are missing. This may be especially problematic for smaller tools which may not be easily seen by the user or which may be obscured by features of the work site.